Simple Amplifier Using LM386

This is the low frequency power amplifier of which the penumbra article can be composed without using it is hardly. The about 660-mW output can be gotten with the 16-ohm speaker.


This circuit is used for the simple monitor and so on. The impedance (4-ohm and 8-ohm, and so on), the output power of the speaker and so on are specified by the standard but are OK rather than strict. Because the sound cracks (warping) when presenting the output above the rating, it uses naturally within the standard. When conscious of the timbre and the output power, it is better not to do the use of this circuit.

Simple HF Bands QRP Linear Amplifier

This is the design for QRP linear amplifier with a wide frequency response; within three dB's from 300KHz to 30MHz. Overall gain is in the region of 16dB and the final output power may be well over four watts. This is the figure of the circuit.


The wide bandwidth is a result of the construction of the RF transformers, T1 and T2. These are wound on 2-hole ferrite balun cores as commonly found in the old fashioned valve TV sets (e.g. Phillips 4322-020-31520). Twist 2 lengths of 22 SWG enamelled wire together and wind as shown. Connect the end of the "A" winding to the start of the "B" winding. Use this junction as the centre-tap of the transformer. This PA will deliver 4 watts continuously (with a suitable heatsink), and may be loaded into a short-circuit or open circuit without causing damage. This makes it almost the ideal PA for outdoor/field use. Above is the full circuit diagram of the RFPA and the coil winding pattern. This PA may be used for for SSB, as well as CW (and AM?).

Simple Voltage Regulator using Op Amp

This circuit is a circuit diagram power supply. Circuit diagram works on voltage +13.8 V 5A with electric currents. This circuit controlled by the LM338 IC. This is the figure of the circuit.


Many times we need a supply of relatively strong in the framework we provide a variety of equipment with + 13.8V, as transceivers CB, cargo lead-acid batteries, and others known to use the circuit capable of providing complete in his exit, when This continuously operating 5A and 12A peak current. Not only need a few external components. Setting the voltage at + 13.8V to the trimmer TR1, (multiturn). The IC1 LM338 must in each case is placed on one suitable heat sink, which both supported by one fan. All the connections by the circuit become with big cross-section cable, because the current through from within their already high enough.

Part:
R1=270R 1/4W 2%
TR1=4k7 (Multiturn)
C1=10000uF 40V
C2-3=100 nF 100V Polyester
C4-5=10uF 25V
D1-2=1N4002 (1A/100V)
B1=25A Bridge Rectifier
IC1=LM338
T1=220Vac/15VAC – 8A Mains Transformer
S1=2 Pole Single Throw Mains Switch

F1=250mA Fuse

Simple Parallel Operation for Power Amplifier

Output drive beyond the capability of one power amplifier can be provided as shown here. This circuit is work with based on LM12 IC. This is the figure of the circuit.


The power op amps are wired as followers and connected in parallel with the outputs coupled through equalization resistors. A standard, high-voltage op amp is used to provide voltage gain. Overall feedback compensates for the voltage dropped across the equalization resistors. With parallel operation, there may be an increase in unloaded supply current related to the offset voltage across the equalization resistors. More output buffers, with individual equalization resistors, may be added to meet even higher drive requirements.

Simple Single Rail Amplifier With True Zero Volt Output Swing

This is a circuit that is performance requirements necessitate analog output current monitors to swing within 100mV of zero. This is the figure of the circuit.

A1, a chopper stabilized amplifier, has a clock output. This output switches Q1, providing drive to the diode-capacitor charge pump. The charge pump output feeds A1’s V– terminal, pulling it below zero, permitting output swing to (and below) ground. If desired, negative output excursion can be limited by either clamp option shown. Reliable start-up of this bootstrapped power supply scheme is a valid concern, warranting investigation. In Figure D2, the amplifier’s V– pin (Trace C) initially rises at supply turn-on (Trace A) but heads negative when amplifier clocking (Trace B) commences at about midscreen.

Simple Microphone Amplifier Circuit

This is a circuit diagram of a device which can hear faint sounds and those sounds which any normal microphone can not hear. This is a very useful circuit and one can use this circuit for many tasks this circuit can be used as a hearing aid. Use direct coupling and do not use bulky coupling or bypass capacitors. The circuit using only a few components the size of the circuit is very small so one can easily fit it in a small box. This is the figure of the circuit;

Capacitor 1 bypasses ac negative feedback due to which the gain is not affected. Q1, Q2 and Q3 are bc 337. Resistor 1 is used for volume control. Transistor 1, transistor 2 and transistor 3 all are direct coupled amps. Their operation is stabilized by direct current (DC) negative feed back through resistor 4.

Simple Audio Power Amplifier Over Temperature Detector

This is a power amplifier for audio that has over temperature detector inside. This circuit is based on LM56 as controller. This circuit has simple form of the design. This is the figure of the circuit.


An audio power amplifier IC is bolted to a heat sink and an LM56 Celsius temperature sensor is mounted on a PC board that is bolted to the heat sink near the power amplifier. To ensure that the sensing element is at the same temperature as the heat sink, the sensor's leads are mounted to pads that have feed through to the back side of the PC board. Since the LM56 is sensing the temperature of the actual PC board the back side of the PC board also has large ground plane to help conduct the heat to the device. The comparator's output goes low if the heat sink temperature rises above a threshold set by R1, R2, and the voltage reference. This fault detection output from the comparator now can be used to turn on a cooling fan. The circuit as shown in design to turn the fan on when heat sink temperature exceeds about 80°C, and to turn the fan off when the heat sink temperature falls below approximately 75°C. [Circuit source: National Semiconductor, Inc Notes].

Simple 80W Operational Amplifier Using LM12

This is a circuit for op amp that is built by LM12. This circuit can deliver 80W of sine wave power into a 4X load with 0.01% distortion. This is the figure of the circuit.


The IC delivers g10A output current at any output voltage yet is completely protected against overloads, including shorts to the supplies. The dynamic safe-area protection is provided by instantaneous peak-temperature limiting within the power transistor array. The turn-on characteristics are controlled by keeping the output open-circuited until the total supply voltage reaches 14V. [Circuit’s source: National Semiconductor Notes].

Simple 22 Watt Audio Amplifier Circuit

This is a design for simple audio power amplifier. This circuit is based on amplifier chip TDA1554 that is has two channel audio chip amp. This is the figure of the circuit.


The circuit can be used as a booster in a car audio system, an amp for satellite speakers in a surround sound or home theater system, or as an amp for computer speakers. The circuit is quite compact and uses only about 60 watts. The circuit works best with 4 ohm speakers, but 8 ohm units will do. The circuit operates at 12 Volts at about 5 Amps at full volume. Lower volumes use less current, and therefore produce less heat.

Part:
R1 39K 1/4 Watt Resistor
C1,C2 10uf 25V Electrolytic Capacitor
C3 100uf 25V Electrolytic Capacitor
C4 47uf 25V Electrolytic Capacitor
C5 0.1uf 25V Ceramic Capacitor
C6 2200uf 25V Electrolytic Capacitor
U1 TDA1554 Two Channel Audio Amp Chip
MISC Heat sink for U1, Binding Posts (For Output), RCA Jacks (For Input), Wire, Board